Generally, in an image forming apparatus using a xerography such as a copier, a printer or a facsimile, in the image forming steps, a roller to which a conductivity is imparted such as a transfer roller, a developing roller, a toner supply roller, a charging roller, a cleaning roller, an intermediate transfer roller or a belt driving roller is used.
As such roller members, ones provided with a basic structure having an elastic layer comprising rubber, polymeric elastomer, polymeric foam or the like to which an electric conductivity is imparted by blending a conductive agent therein, which elastic layer is formed on the outer periphery of the shaft; and further with a single or multiple coating layers on the outer periphery of the layer to attain a desired surface roughness, conductivity, hardness and the like; have been conventionally used.
As the technique related to a conductive roller, for example, Patent Document 1 discloses a technique in which a metal plating layer is provided on the outer surface and the inner surface of an elastic resin roller portion in a conductive roller provided with a shaft and a continuously foamed elastic resin roller portion which is bonded to the periphery surface of the shaft excepting at least one of the exposed ends of the shaft via an adhesion layer, for the purpose of obtaining a conductive roller having an elasticity and provided with an intermediate resistance of about 103Ω to 106Ω with small resistance variability.